During the past year a number of strategies for treating retroviral infections has emerged. It is now appreciated that every step in the life cycle of pathogenic human retroviruses could theoretically serve as a target for antiviral therapy. In particular, the process of reverse transcription appears to be an attractive target with practical results already at hand. A number of drugs and pharmacologic principles relevant to the administration of such drugs have been identified in the Clinical Oncology Program for application in the therapy of diseases mediated by pathogenic human retroviruses. One family of such drugs (dideoxy-nucleoside analogues) shows special promise. These drugs are now being administered to patients with AIDS and its related disorders. One drug in the family, AZT, has already reached prescription drug status.